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Concentration of lead have been determined in three species of small mammal, Sorex araneus, Clethrionomys glareolus and Apodemus sylvaticus at roadside and control sites. The results are considered in relation to the lead content of the diet and the air, and it is concluded that the diet provides far the major pathway for lead exposure, even at the roadside site. Bone lead concentrations are found to be consistent with estimated lead exposure and metabolism.

Mirex, the only compound approved for control of the red imported fire ant (Solenopsis invicta) and the black imported fire ant (Solenopsis richteri), is normally applied at a rate of 1.40 kg/ha. (1.25 lb/acre). Influenced by recent studies showing that low levels of mirex are toxic to certain nontarget organisms, particularly estuarine species, authors report here on a monitoring study of mirex in three large treatment areas of southwest Georgia. Four formulations of bait were applied aerially in 1971-72. Low-level residues were observed in small terrestrial vertebrates and invertebrates and in fresh-water inhabitants. Levels detected were about the same for all baits. Maximum residues were detected 1-3 months after treatment and gradually declined to low levels of 0.02-1.16 ppm 1 year after treatment.

Lead levels in small mammals were studied in 6 areas -- 3 associated with highways of different traffic densities, and 3 control sites in forested areas. Lead levels were also studied in insects from 2 traffic areas and in earthworms from different distances from 2 traffic areas. Lead levels were low in insects ranging from 3.84 microng/g to 3.35 microng/g. Lead levels in earthworms were highest in those recovered closest to highways and from the area with the higher traffic volume. Lead levels in mammals generally was highest in mammals from areas of higher traffic densities. Higher levels of lead were found in shrews than in Peromyscus and Microtus.

1. The amounts of tissue lipids were higher in S. etruscus than in C. russula. 2. The level of liver phospholipids was specially low in C. russula, 2650 mg/100 g as opposed to 3725 g in S. etruscus. 3. This is in good agreement with a reduced rate of the labelled acetate incorporation into the lipids of C. russula. 4. The proportion of unsaturated fatty acids was greater in the liver of S. etruscus; however, the percentage of arachidonic acid was higher in C. russula--15% as opposed to 8%.

Physical and chemical agents present in the environment can potentially damage mammalian DNA. Such damage is known in some cases to be repaired by the process of DNA excision repair. This process has been extensively studied utilizing the repair of ultraviolet irradiation damage as a model system. In this study we have used this system and the 5-bromodeoxyuridine photolysis assay to measure DNA excision repair in cells derived from 21 mammalian species. We have attempted to relate the DNA repair proficiencies and the average size of the repaired regions seen in the cell cultures with the various maximum life spans of the mammals studied. There was an approximate linear correlation between life span of the mammals and the number of DNA excision repair sites measured 20-22 hours following ultraviolet irradiation of the cell cultures. Several deviations from the linear relationships were observed which remain largely unexplained. The size of the repaired regions was shown not to be related to the maximum life spans of the mammals tested.

A chronic hypercalcaemia was induced in Suncus murinus by the daily subcutaneous injections of parathormone for 15 days. Serum calcium increased 4 hours after the first injection (+ 0.88 mg/100 ml), it reached its highest value on day 10 (+ 2.18 mg/100 ml), and then decreased slightly at the end of the experiment (day 15). The serum phosphate level in treated animals showed a progressive fall throughout the experiment. Serial sections of thyroid-parathyroid complex were subjected to selective staining for C cells identification. The chronic hypercalcaemia increased the number of C cells. This was supported by the presence of mitotic figures. Degranulation of the secretory material was observed as the result of the chronic hypercalcaemia; degenerative changes were found in some C cells. The chronic hypercalcaemia also inhibited the activity of parathyroid "Chief-Cells" which ultimately degenerated.

The substrate specificity and other properties of a fatty acid hydroxylase system in liver microsomes of the Japanese house musk shrew, Suncus murinus, were examined. Shrew liver microsomes catalyzed the hydroxylation of various saturated fatty acids (C8-C18) to the corresponding omega- and (omega-1)-hydroxy derivatives. The relative activities of the hydroxylase with these substrates were as follows: C12 (100, actual conversion: 7.05 nmol/mg of microsomal protein/min), C10 (90), C14 (87), C16 (23), C8 (19), and C18 (11). The specific activity of the fatty acid hydroxylase in shrew liver was much higher than that in other species. The omega/omega-1-hydroxylation ratio decreased with increasing chain length of fatty acid substrates (C10-C18), but it was 0 for the C8 fatty acid. Both NADPH and O2 were required for hydroxylase activity, and NADH had little effect. The apparent Km value for laurate was 1.6 X 10(-5) M. The hydroxylase activity was 92% inhibited by CO at a CO-O2 ratio of 9. p-Chloromercuribenzoate (0.1 mM) inhibited hydroxylation by 94% whereas iodoacetate (0.1 mM) inhibited it by only 8%. SKF 525-A (1 mM) and menadione (0.01 mM), respectively, caused 41% and 29% inhibition of the activity. It is concluded that the hydroxylase catalyzing fatty acid hydroxylation in shrew liver microsomes is a typical cytochrome P-450-linked monooxygenase.